DE8618985U1 - Mount for a lens attachment - Google Patents

Description

I'.et''a' I ' ³ '&udigr;'',&idigr;' Alfred Chrösziel

&THgr;&Ogr;&Ogr;&Ogr; Munich

Mount for a lens attachment

The invention relates to a holder according to the preamble of claim 1. Such holders are used for larger lenses that are used in professional film cameras and television cameras. An object holder is provided here, which is usually integrated with the camera holder. This object holder is usually arranged movably on a stable tripod.

Such lenses sometimes have a relatively large diameter. The same applies to the attachments that are tailored to the lenses, such as the lens hood, often also called a matte box, for filter holders or a combination of lens hood and filter holder. These attachments must fit tightly around the lens in order to largely eliminate stray light. The connection is usually made via a flexible bellows. The attachment must have a sufficiently large opening at the front so that none of the image field is covered even with lenses with a longer focal length. Furthermore, only specific attachments that are tailored to specific focal length ranges can be used. The attachments are so bulky and heavy that unscrewing them or something similar, as with amateur cameras, is no longer advisable . For this reason, such attachments are connected to the lens mount via a sliding mechanism in order to be able to swing the entire attachment forwards, in particular to enable the bellows that encloses the lens at its free front end to be removed. Furthermore, such a holder has a swivel mechanism in the form of a two-part joint, which allows the entire attachment part to be swiveled sideways or upwards or downwards after the holder has been pushed forwards.

With known holders for lens attachments, the attachment must first be laboriously pulled forward, then a lock for the swivel mechanism is released and the attachment is pulled out of the angle of view of the lens -

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swivels in order to carry out the necessary work, which usually involves removing the lens to check and, if necessary, clean the film stage or to replace it with another lens. Then the same work processes have to be carried out in reverse order . Sliding it out is laborious/releasing the lock is awkward/which, in the case of a hasty lens change due to the situation, can also lead to certain scenes not being able to be recorded correctly.

The invention is based on the object of designing a holder according to the preamble of claim 1 in such a way that the triggering of the swivel mechanism is simplified.

The object is achieved according to the invention by the features of the characterizing part of claim 1. Further embodiments of the invention are protected in the subclaims.

A key idea behind the invention is to couple the locking mechanism of the swivel mechanism with the sliding mechanism of the attachment holder in such a way that the locking mechanism is automatically released after the attachment is pushed forwards and that it automatically re-engages after the attachment is pushed back onto the lens. This is achieved by providing locking openings in the pivoting outer link of the joint that are aligned with the guide rails for the attachment. When the attachment is placed on the lens, the guide rails engage in these locking openings; when the attachment is pushed forwards, the free ends of the guide rails emerge from the locking openings, so that the swivel mechanism is automatically released.

In a preferred embodiment, a drive is provided between the fastening frame for the stationary ends of the guide rails and the inner link of the joint, which can push the attachment part back and forth by defined distances. Various means can be used for such a drive

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For example, an electric motor, a rack with a rotating gear, or a spring mechanism.

Preferably, the drive consists of an eccentric, a lever attached to it and a swivel member pivotally mounted on the inner member of the joint, the free end of which is pivotally connected to the free end of the eccentric, the other end of the eccentric being pivotally mounted on the fastening frame for the stationary ends of the guide rails. The length of the guide rails, the size ratios and the dimensional ratios of the eccentric and swivel member can be dimensioned such that «a rotation of the eccentric in a first direction by 180 ° results in a defined contact of the attachment part with the lens and a rotation by 180 in the opposite direction results in a

Sliding the attachment part away from the lens by a defined distance and simultaneously releasing the locking openings. The middle section of the swivel element can be designed in an arc shape, which makes handling and, if necessary, the torque required to operate the drive easier.

With such a drive, the attachment part attached to the lens can be pushed forward with a single lever movement by a precisely defined amount and with little effort up to a stop after a 180° rotation.

The rotating mechanism is then immediately released and the attachment can be swiveled out of the lens's image field to carry out work, such as changing the lens. After the attachment has been swiveled back into the lens's optical axis, a single lever movement of 180° in the opposite direction locks the bellows of the attachment diaphragm and precisely re-attaches it to the lens.

Furthermore, due to the existing friction conditions, intermediate positions of the lever are possible up to a certain degree. This results in either a slightly different

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Distance of the attachment part 2 um lens. This changes the angle of incidence ratios on the attachment part. This means that such an attachment part can be used for a somewhat larger range of lens focal lengths. On the other hand, this intermediate position of the shift lever enables the use of lenses of different lengths to a certain extent. In this case, an intermediate position of the shift lever can enable the bellows to be placed precisely on the end of the lens for different lens lengths.

The holder allows one-handed operation with minimal effort, whereas previously a laborious shifting under

Use of both hands and a risk of maladjustment of the entire camera tripod was required.

* Embodiments of the invention are shown in the drawing

shown.

It shows:

Fig. 1 is a plan view of a side mount with the lens attachment pushed forward,

Fig. 2 shows the illustration of Fig. 1 with the attachment attached to the lens,

Fig. 3 is a side view of Fig. 1,

Fig. 4 is a side view of Fig. 2.

In the drawing, identical parts are provided with identical reference numerals. In Fig. 1, the attachment part is designated with (1), the optical axis of the lens (23) is designated with (2). The lens (23) is connected to the lens holder (9) via an intermediate member (24). For the sake of simplicity, the other components, in particular the light transmission path from the lens (23) to the camera (not shown) provided behind the lens holder (9), the camera

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tripod, to which the lens holder (9) is attached, etc. not shown.-

Below the lens (23) there are two axially parallel rails (25) and (26), on which a fastening frame (18) is slidably arranged. On one side of the fastening frame (18) there is a guide rail (3) parallel to the optical axis (2), the fixed end (5) of which is rigidly connected to the fastening frame (18). Parallel to the fastening frame (18) there is an outer member (14) of a joint which is connected to the inner member (10) via a connecting joint member (13), which is arranged parallel to the outer member (14). The inner member (10) has a guide (11) (and underneath there is another guide (12) on another guide rail (4), see side view Fig. 3 and Fig. 4), which can be moved on the guide rail (3). As a result, the outer member (14) connected to the inner member (10) and the entire attachment part (1) connected to the outer member (14) also shift.

In Fig. 1, a mechanical drive (17) is also shown. The drive (17) essentially consists of an eccentric (19), a pivoting member (22) and a sliding lever (20). The front section of the pivoting member (22) is rotatably mounted on the inner member (10) of the joint, the free rear end of the pivoting member (22) is rotatably connected to the free end of the eccentric (19), while the other end of the eccentric

(19) is rotatably mounted on the mounting frame (18). Near the latter bearing, a shift lever is mounted on the eccentric 19

(20) is provided which has openings into which, if necessary, a rod can be inserted to facilitate the rotation of the lever (20).

Fig. 2 shows essentially the same arrangement as Fig. 1, However, the attachment part (i) is placed on the front flange of the lens (23). Heating was carried out with

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With the aid of a mechanical drive, the displacement lever (20) is rotated by 180°. Compared to Fig. 1, the free end (7) of the guide rail (3) projects through the locking opening (15) of the outer member (14) of the joint, so that the attachment part (1) is fixed against pivoting movements. The bellows (27) at the rear end of the attachment part (1) encloses the free front end of the lens (23). Fig. 2 also shows that the eccentric (19) is rotated backwards by 180° , as is the displacement lever (20) connected to it. Rotating the lever (20) backwards by 160° thus causes the eccentric (19) connected to it, which is mounted on the free end of the pivoting member (22), to rotate in the same way. As a result, the joint connected to the pivot member (22) and the associated attachment part (1) are pushed backwards.

Fig. 3 shows a side view of the holder shown in Fig. 1, i.e. with the attachment part (1) pushed forward. From Fig. 3 it can be seen in particular that two guide rails (3) and (4) are arranged parallel to one another and parallel to the optical axis (2), the rear fixed ends being fastened to the fastening frame (18), which is guided downwards and inwards and is in turn connected, preferably pivotably, to a rail (25) (and 26, Fig. 1) which is connected to the lens holder (9).

The shift lever (21) is shown here at an angle downwards and forwards for better clarity, although it is preferably in the same plane as the eccentric (19). To simplify handling and, if necessary, to improve the torque, the middle section of the swivel link (22) is curved, preferably upwards. Fig. 3 also shows the joint, with the inner link (10), the outer link (14) and the joint link (13) in between. The inner link (10) has guides (11) and (12) for the upper (3) and the lower (4) respectively.

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lower guide rail (4), the outer link (14) has locking openings (15) and (16) which are aligned with the free ends (7) and (3) of the guide rails (3) and (4).

Fig. 4 shows the representation of Fig. 2, ie with the attachment part (1) attached to the lens. Compared to Fig. 3, it can be seen that the attachment part (1) is pushed backwards, ie to the left, so that the free ends (7) and (8) of the guide rails (3) and (4) pass through the locking openings (15) and (16) of the outer member (14). On the other hand, Fig. 4 shows the eccentric (19) and the associated shift lever (21) being turned 180° anti-clockwise.

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Claims (4)

Expectations 1. Holder for - a lens attachment (1) such as a sun visor, a filter holder or a sun visor with integrated filter holder, with at least one guide rail (3, 4) arranged parallel to the lens axis (2), one end (5, 6) of which is fixedly connected to the lens holder (9), while a two-part joint is arranged at the other two free ends (7, 8), the inner member (10) of which can be moved on the guide rails (3, 4) via guides (11, 12) , and the outer member (14) of which is connected to the inner member (10) via a joint member (13) and is connected to the attachment (1), the inner member (10) and outer member (14) being arranged essentially parallel to one another and at right angles to the guide rails (3, 4), characterized by a locking opening (15, 16) aligned with the guide rail (3, 4) on the outer link (14) of the joint. 2. Holder according to claim 1, characterized by a drive (17) between the fastening frame (IB) for the stationary ends (5,6) of the guide rails (3,4) and the inner member (10) of the joint for pushing the attachment part (1) back and forth over defined paths. 3. Holder according to claim 2, characterized in that the drive (17) consists of an eccentric (19), a lever (20; 21) attached thereto and a pivoting member (22) pivotably mounted on the inner member (10), the free end of which is connected in an articulated manner to the free end of the eccentric (19), the other end of the eccentric (19) being pivotally mounted on the fastening frame (18), and the length of the guide rails (3, 4) and the size ratios of the eccentric (19) and pivoting member (22) being dimensioned such that a rotation of the eccentric (19) by 180° in a first direction (a defined contact of the attachment part (i) on the lens (23), and a rotation by 180° in the opposite direction a 1 a · Γ * J I · f« 2fl Sliding the attachment part (1) away from the lens (23) by a defined distance and simultaneously releasing the locking openings (15,16). 4. Holder according to claim 3, characterized in that the central portion of the pivot member (22) is arcuate. I Il · it . .** . · 4